package com.acanx.util;

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.List;
import java.util.Map;

/**
 *    ACANX-Util / com.acanx.utils / HttpUtil
 *   文件由 ACANX 创建于 2019/1/5 . 15:46
 *  HttpUtil:
 *  补充说明：
 *  2019/1/5  15:46
 *
 *  @author ACANX
 *  @since 0.0.0.1.6
 */
public class HttpUtil {
    /**
     * 构造函数
     * @hidden
     */
    private HttpUtil() {
    }

    /**
     *      POST请求
     *
     * @param requestUrl   请求路径
     * @param accessToken  accessToken
     * @param params       请求参数
     * @return             请求结果
     * @throws Exception   Exception
     */
    public static String post(String requestUrl, String accessToken, String params)
            throws Exception {
        String contentType = "application/x-www-form-urlencoded";
        return HttpUtil.post(requestUrl, accessToken, contentType, params);
    }

    /**
     *   post请求方法
     *
     * @param requestUrl 请求地址
     * @param accessToken accessToken
     * @param contentType contentType
     * @param params  参数
     * @return       请求结果
     * @throws Exception  Exception
     */
    public static String post(String requestUrl, String accessToken, String contentType, String params)
            throws Exception {
        String encoding = "UTF-8";
        if (requestUrl.contains("nlp")) {
            encoding = "GBK";
        }
        return HttpUtil.post(requestUrl, accessToken, contentType, params, encoding);
    }

    /**
     *   POST请求
     *
     * @param requestUrl  请求路径
     * @param accessToken  accessToken
     * @param contentType  contentType
     * @param params       参数
     * @param encoding     编码
     * @return             请求结果
     * @throws Exception   Exception
     */
    public static String post(String requestUrl, String accessToken, String contentType, String params, String encoding)
            throws Exception {
        String url = requestUrl + "?access_token=" + accessToken;
        return HttpUtil.postGeneralUrl(url, contentType, params, encoding);
    }

    /**
     *  POST请求生成方法
     *
     * @param generalUrl   请求路径
     * @param contentType   contentType
     * @param params      请求参数
     * @param encoding    编码
     * @return            请求结果
     * @throws Exception  Exception
     */
    public static String postGeneralUrl(String generalUrl, String contentType, String params, String encoding)
            throws Exception {
        URL url = new URL(generalUrl);
        // 打开和URL之间的连接
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("POST");
        // 设置通用的请求属性
        connection.setRequestProperty("Content-Type", contentType);
        connection.setRequestProperty("Connection", "Keep-Alive");
        connection.setUseCaches(false);
        connection.setDoOutput(true);
        connection.setDoInput(true);

        // 得到请求的输出流对象
        DataOutputStream out = new DataOutputStream(connection.getOutputStream());
        out.write(params.getBytes(encoding));
        out.flush();
        out.close();

        // 建立实际的连接
        connection.connect();
        // 获取所有响应头字段
        Map<String, List<String>> headers = connection.getHeaderFields();
        // 遍历所有的响应头字段
        for (String key : headers.keySet()) {
            System.err.println(key + "--->" + headers.get(key));
        }
        // 定义 BufferedReader输入流来读取URL的响应
        BufferedReader in = null;
        in = new BufferedReader(
                new InputStreamReader(connection.getInputStream(), encoding));
        String result = "";
        String getLine;
        while ((getLine = in.readLine()) != null) {
            result += getLine;
        }
        in.close();
        System.err.println("result:" + result);
        return result;
    }
}
